▎ 摘　　要

NOVELTY - Method for preparing sulfonic acid-modified graphene, involves (i) uniformly mixing graphite raw material and sulfonic acid-based grinding agent, adding solvent (M), and mechanically stirring to obtain a dispersion liquid, (ii) pouring the dispersion liquid obtained in step (i) to a ball-milling tank, adding grinding ball, and ball-milling to obtain a sulfonic acid-modified graphene slurry, and (iii) concentrating, ultrasonically dispersing, filtering and drying the sulfonic acid-modified graphene slurry obtained in step (ii) to obtain sulfonic acid-modified graphene powder. USE - The method is useful for preparing sulfonic acid-modified graphene which is used for aqueous epoxy coating (all claimed). ADVANTAGE - The aqueous epoxy coating prevents the coating from cracking, and has excellent salt spray resistance and corrosion resistance. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a sulfonic acid-modified graphene prepared by the above method with a sheet diameter of 5-10 mu m and sheet thickness of less than 5 nm; and (2) use of the sulfonic acid-modified graphene for an aqueous epoxy coating comprising component (A) and component (B) in a mass ratio of 100:(40-80), where the component (A) comprises 10-20 pts. wt. curing agent, 5-30 pts. wt. solvent (N), 40-80 pts. wt. antirust filler, 10-40 pts. wt. functional filler, 1-10 pts. wt. co-solvent, 1-10 pts. wt. additive and 0-1 pts. wt. sulfonic acid-modified graphene powder, and the component (B) is an aqueous epoxy emulsion.